v3.19.3.a.u2
Summary of Significant Accounting Policies - Schedule of Cash and Cash Equivalents and Restricted Cash (Detail) - USD ($)
$ in Millions
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Accounting Policies [Abstract]        
Cash and cash equivalents $ 6,268 $ 3,686 $ 3,368 $ 3,393
Restricted cash, current portion 246 193 155 106
Restricted cash, net of current portion 269 398 442 268
Total as presented in the consolidated statements of cash flows $ 6,783 $ 4,277 $ 3,965 $ 3,767